Apparatus for processing yarn



Dec. 20, 1966 F. E. CHALFANT ET AL APPARATUS FOR PROCESSING YARN FiledApril 20, 1965 2 Sheets-Sheet 1 INVENTORS. v FREDERIC E. CHALFANT GUY E.PERKINS I ATTYS.

United States Patent 3,292,354 APPARATUS FOR PROCESSING YARN Frederic E.Chalfant and Guy E. Perkins, Warwick, R.I., assignors to LeesonaCorporation, Warwick, R.I., a corporation of Massachusetts Filed Apr.20, 1965, Ser. No. 449,487 7 Claims. (Cl. 57-34) The present inventionrelates to apparatus for the processing of yarn having thermoplasticqualities, and has particular application to an improved heating meansfor controlling the temperature of the yarn in connection with thetexturizing thereof.

Prior to the present invention it has been the practice to process yarnshaving thermoplastic qualities to form textured yarns such as torquestretch yarns, bulk yarns, and the like, by methods including the stepof passing the yarn through a heating zone which elevates thetemperature of the yarn to a level at which the molecules of the yarnmay be reoriented so that upon cooling the yarn is possessed of apermanent set characterized by a tendency of the yarn to return to thecondition it had at the time of heating. When making torque stretchyarns, while passing through the heating zone, the yarn is twisted sothat the processed yarn has a tendency to return to the twistedcondition when it is later untwisted. The twisting and untwisting isnormally accomplished by a false twist means such as a spindle whichimparts twist to the yarn in advance of the spindle and permits removalof the twist following passage through the spindle. During thisprocessing, the tension and the heat applied to the yarn are correlatedto the linear travel of the yarn through the heating zone and to thedegree of twist which is imparted to the yarn by the false twistingspindle.

The linear speed of yarn thorugh the heating zone has been increasedsubstantially with the improvement of the processing apparatus, and ithas been found that a twist gradient exists within the heating zone,which gradient increases as the speed of travel increases. At slowspeeds,

the twist gradient is confined to a short length of yarn at the entranceend of the twisting zone. At higher speeds, however, the length of yarnwhich possesses the twist gradient increases to an extent that atextremely high speeds the heat and tension do not have the same correlation to the twist throughout the entire heating zone as they do at thelower speeds. It has further been discovered that the length of thetwist gradient in the yarn is greater when the yarn is cool than whenthe yarn is heated, and with prior art apparatus operating at extremelyhigh speeds, the temperature of the yarn does not attain the desiredsetting temperature until it has traveled some distance into the heatingzone.

With the foregoing in mind, it is a primary object of the presentinvention to provide improved apparatus which effectively preheats theyarn prior to its entry into the heating and twisting zone so as toaccelerate the heating of the yarn within the zone and thereby reducethe time interval within the heating and twisting zone which is requiredto cause the yarn to attain the desired heat setting temperature.

More specifically the present invention provides a novel preheater foryarn which elevates the temperature of the yarn to a point below thetemperature necessary for molecular reorientation of the yarn, inadvance of its entry into the twisting and heating zone of theprocessing apparatus.

The present invention provides apparatus insuring preheating of the yarnwithout imparting additional twist to the yarn during the preheatingoperation so that the entire twist of the yarn is added in the heatingand twisting zone per se.

The present invention provides tension control for the yarn in thepreheating zone to control the tension thereof in correlation to thesize of the yarn, the speed thereof, and the temperature of thepreheater.

All of the objects of the invention are more fully set forth hereinafterwith reference to the accompanying drawing in which:

FIG. 1 is a transverse sectional view through a multistation yarnprocessing apparatus embodying a preheating device in accordance withthe present invention;

FIG. 2 is a fragmentary view in front elevation of the apparatus shownin FIG. 1;

FIG. 3 is a perspective view of the preheater embodiment embodied in theapparatus of FIGS. 1 and 2;

FIG. 4 is a sectional view on a horizontal plane through the preheatershown in FIG. 3; and

FIG. 5 is a fragmentary view similar to FIG. 3 illustrating anotherembodiment of preheater for use in connection with apparatus similar tothat shown in FIGS. 1 and 2.

The apparatus of FIGS. 1 and 2 is basically similar to that shown in US.Patent No. 3,152,436 issued October 13, 1964 to C. J. Dudzik et al. Thisapparatus comprises a multistation machine, each station including twofalse twist spindles 10 and 20 operable to be rotated at a speedcommensurate with the rate of travel of the yarn therethrough andincluding a twist trapper therein for twisting the yarn below thespindle and untwisting the yarn above the spindle. The untwisted yarnfrom each spindle is passed around a pair of tension-controlling feedrollers 11, 21 and from there to a processed-yarn take up device 12, 22.The take up device 12 for the spindle 10 is disposed below and in frontof the feed rolls 11 and the takeup device 22 for the spindle 20 isdisposed a like distance above and in front of the feed rolls 21.

A heating and twisting zone underlies each of the spindles 1t) and 20and includes a heater plate 31 common to all of the heating zones whichis heated by suitable heating elements 32 extending along the length ofthe multi-station apparatus. The heater plate is surrounded by blockinsulation 33 having grooves or slots 14 and 24 respectively inalignment with the spindles 10 and 20. A threading device 34, such asshown in Dudzik Patent No. 3,094,761, is operatively associated with theheater plate 31 to facilitate threading of the yarns through the groovesor slots 14 and 24. Means is provided at 15 and 25 respectively toarrest the travel of the twist from the opera-. tion of the spindles 10and 20 so that the yarn in advance of the twist trappers 15 and 25 hasthe same twist condition that it possesses on the supply packages 16 and26. As shown, the yarn from the packages 16 and 26 is passed upwardlytoward the heating zone through suitable disc tensions 17 and 27respectively.

The disc tensions 17 and 27 isolate the packages from the remainder ofthe apparatus so that variations in tension occasioned by the unwindingof yarn from the packages are controlled as the yarn passes beyond thedisc tensions.

In accordance with the invention, heated feed roll assemblies 19 and 29respectively are mounted intermediate the disc tensions 17, 27 and thetwist trappers 15, 25. As shown, the heated feed roll assemblies 19 and29 are similar in construction and only the assembly 19 will bedescribed in detail. As shown in FIGS. 3 to 5, the assembly 19 includesa heater plate 41 having heating elements 42 associated therewith tomaintain the desired temperature in the heating plate. Projectingforwardly from the heater plate 41 are cylindrical heater blocks 43 and44 secured in heat-conductive relationship to said heater plate andserving as heat sinks. The heater plate and blocks are provided withbores 45 and 46 adapted to mount therein drive shafts 47 and 48. Thedrive shafts are provided with sleeve bushings 49 and 50 to affordrotary movement of said shafts within said blocks. Feed rolls aremounted on the the shafts 47 and 48 and, in the present instance,consist of hollow cylindrical shells 53 and 54 surrounding thecylindrical blocks 43 and 44 respectively and rotatable thereon byreason of a keyed connection at 55 and S6 to the drive shafts 47 and 48respectively. It should be noted that the heater plate 41 is offsetrearwardly from the heater plate 31, so that the yarn, as it leaves theroll 54, is in vertical alignment with the heating surface of the plate31 and is free to bear against the plate in heat-transfer relationshiptherewith. As shown in FIG. 1, the drive shafts 47 and 48 have suitablygeared driving connections 55 to drive the rolls 53 and 54 at the samesurface speed. The entire assembly is contained in an insulated housing,in the present instance formed in two parts 57 and 58 respectively, thefront part 58 being readily removable for threading up and forobservation of the passage of the yarn over the feed rolls.

In the embodiment shown in FIGS. 1 to 4, the shells 53 and 54 aregrooved as indicated to maintain the yarn runs about the feed rollsseparated as they travel thereon. The surface of the grooved rolls ispreferably highly polished or sufficiently smooth to afford freedom. forthe yarn to slip thereon, permitting contraction or shrink- I age of theyarn as it travels over the heated feed rolls The upper feed rolls 11,21 and the lower feed roll assemblies 19, 29 are correlated in speed toimpart the desired tension to the yarn in the heating and twisting zonebelow the false twist device 10, 20. The tension heating and twistingzone. In the present instance, the

nip of said rollers 154 and 160 is in vertical alignment with the groove114 of the overlying heater assembly. The roller 160 is similar inconstruction to the roller 154, consisting of a cylindrical shellmounted for rotation on a cylindrical heater block which is secured to ia lever 162 pivoted to the heater plate as indicated at 163 provide apositive pinch between the rollers 160 and on the yarn in the preheatingzone within the heated feed roll assembly 19 is controlled by the numberof runs or wraps of the yarn around the rolls 53 and 54, taking intoconsideration the tension imparted by the disc tensions in advancethereof. The tension desired in the preheating zone on the heated feedrollers is dictated by the speed and denier of the yarn and thetemperature of the preheater in relation to the amount of shrinkagewhich is desired in this zone. For example, when operating the heatingand twisting zone in the range of 430 F. to 480 F., as when processingnylon, the temperature of the preheating zone should be in the range of270 F. to 330 F. This temperature range, which is below the temperaturenecessary to reorient the molecules of the nylon, provides the bestresults with respect to skein shrinkage, strength, and elongation of thenylon being texturized. The number of filaments, the denier, and thetype of nylon determine the specific temperatures desirable foroperation, as is now well known in the art. It i has been found that thegreatest uniformity in the finished texturized yarn has been obtainedwhen the tension on the yarn in the preheating zone is maintained at aminimum value to afford maximum shrinkage of the yarn while obtainingfull heating of the yarn to the temperature level desired.

In many instances it is preferred to employ a straightsurfaced ornongrooved feed roller in the preheater and to employ a positive nipbetween cooperating nip rollers as the yarn enters the preheater and asthe yarn leaves the preheater. When using a positive nip, the twisttrapper of the previous embodiment may be bypassed, or omitted entirely.FIG. 5 shows at 119 an embodiment of preheater employing a nip rollercooperating with the main feed roller in a yarn preheater. To this end,the preheater 119 is constructed similarly to the preheater 19 includinga heater plate 141 having heating elements 142 and feed rollers 153 and154. A twist trapper 115 is provided in the event that it is desired.The feed rollers 153 and 154 are positively driven in a manner similarto the rollers 53 and 54, but the roller 154 has a smoothcircumferential surface in lieu of the grooved surface used in theprevious embodiment. A smooth nongrooved nip roller 160 is provided tobear against the surface of the roller 154 at the point where the yarndisengages the roller 154 in its passage beyond the preheater into the154 to prevent travel of the twist into the yarn wrapped around therolls 153 and 154 and to insure effective heattransfer contact betweenthe yarn and the surface of the rolls. identical to the assembly 19described above.

It is apparent that the novel preheater assemblies of the presentinvention afford fully effective heating of the yarn up to the desiredtemperature level in a minimum of.

space and with maximum effectiveness. Proper preheating of the yarnreduces the time required for the yarn to reach the setting temperaturein the heating and twisting zone which is necessary to effectreorientation of the molecules of the yarn to yarn set the same with theresult that the total twist imparted to the yarn by the false twistingdevice is effective throughout the entire length of the.

heating zone and the treatment of the yarn is therefore uniformregardless of the linear speed of yarn travel through the apparatus,thereby providing greater uniformity in the textured yarn producedthereon.

While particular embodiments of the present invention has been hereinillustrated and described it is not intended to limit the. invention tosuch disclosure but changes and modifications may be made therein andthereto within the scope of the following claims.

What is claimed is:

1. In apparatus for processing yarn having thermoplastic qualitiescomprising false-twisting means operable to twist the yarn in advancethereof and to untwist the yarn thereafter, a heating zone in advance ofsaid false twist means operable to heat the yarn to a temperaturesufficient to afford molecular reorientation of the molecules of theyarn while it is twisted, supply means for said yarn to supply yarn tosaid heating zone, delivery feed rolls to receive the untwisted yarnfrom said false twist means, and yarn take up means operable to collect.the yarn from said delivery feed roll means; the improvement comprisinga preheating assembly intermediate said supply means and said twistingand heating zone to uniformly heat the yarn to a temperature below thetemperature necessary to effect reorientation of the molecules of theyarn, said preheater assembly comprising a pair of spaced apart feedrolls, drive means for said feed rolls operable in timed relation to thedelivery feed rolls so as to control the tension of the yarnintermediate said delivery and said preheater feed rolls, and means toheat said preheater feed rolls to a preselected temperature to effectheating of the yarn to the desired temperature below the temperaturenecessary to effect reorientation of the.

molecules of said yarn.

2. A preheater assembly according to claim 1 wherein said preheaterassembly comprises a heater plate, means to heat said plate to apredetermined temperature, and heater blocks projecting outwardly fromsaid plate and connected thereto in heat-transfer relationshiptherewith, said preheater feed rolls comprising cylindrical shellssurrounding said blocks .and mounted for rotation relative thereto, saidblocks serving as heat sinks to maintain the temperature of saidpreheater feed rolls at said preselected temperature level.

3. A preheater assembly according to claim 2 wherein.

said blocks are cylindrical in form whereby said shells closely surroundsaid blocks to be heated thereby.

In other respects, the preheater assembly 119. is

4. Apparatus according to claim 1 wherein said heated feed-rolls consistof a large roller and 'a small roller said rollers being spaced apartand driven at the same surface speed.

5. Apparatus according to claim 4 wherein said rollers are grooved toreceive and maintain separate the successive runs of yarn wrappedtherearound.

6. Apparatus according to claim 4 wherein said large roller isstraight-surfaced, and including a straight-surfaced nip roller biasedinto engagement with said large roller to eifect a positive nip on theyarn as it enters and leaves said heated feed rolls.

7. Apparatus according to claim 4 wherein the nip of saidstraight-surfaced rollers is disposed in vertical alignment with yarnpath in said heating and twisting zone.

References Cited by the Examiner UNITED STATES PATENTS Stockly 57-34Ubbelohde 57-34 Maier et al. 57-34 Evans 57-34 Enneking 5734 Wegener etal 57-34 Crouzet 57-157 FRANK J. COHEN, Primary Examiner.

15 D. E. WATKINS, Assistant Examiner.

1. IN APPARATUS FOR PROCESSING YARN HAVING THERMOPLASTIC QUALITIESCOMPRISING FALSE-TWISTING MEANS OPERABLE TO TWIST THE YARN IN ADVANCETHEREOF AND TO UNTWIST THE YARN THEREAFTER, A HEATING ZONE IN ADVANCE OFSAID FALSE TWIST MEANS OPERABLE TO HEAT THE YARN TO A TEMPERATURESUFFICIENT TO AFFORD MOLECULAR REORIENTATION OF THE MOLECULES OF THEYARN WHILE IT IS TWISTED, SUPPLY MEANS FOR SAID YARN TO SUPPLY YARN TOSAID HEATING ZONE, DELIVERY FEED ROLLS TO RECEIVE THE UNTWISTED YARNFROM SAID FALSE TWIST MEANS, AND YARN TAKE UP MEANS OPERABLE TO COLLECTTHE YARN FROM SAID DELIVERY FEED ROLL MEAS; THE IMPROVEMENT COMPRISING APREHEATING ASSEMBLY INTERMEDIATE SAID SUPPLY MEANS AND SAID TWISTING ANDHEATING ZONE TO UNIFORMLY HEAT THE YARN TO A TEMPERATURE BELOW THETEMPERATURE NECESSARY TO EFFECT REORIENTATION OF THE MOLECULES OF THEYARN, SAID PREHEATER ASSEMBLY COMPRISING A PAIR OF SPACED APART FEEDROLLS, DRIVE MEANS FOR SAID FEED ROLLS OPERABLE IN TIMED RELATION TO THEDELIVERY FEED ROLLS SO AS